If the high bit in a mask is set, for instance if the mask is
0xff000000, and we shift it to the right by 24 positions, since the mask
was not declared as unsigned we ended up with a mask value of
0xffffffff. We then add 1 to this value and divide by the result,
causing a division by zero crash.
The masks need to be declared unsigned to prevent sign bit extension
when shifting right.
Task-number: QTBUG-29194
Change-Id: I79260344cebfbdd3ea86416a9c734dca76517999
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
